Isolation of Acanthamoeba isolates belonging to T2, T3, T4 and T7 genotypes from environmental samples in Ankara, Turkey

Acanthamoeba keratitis is a blinding infection that is becoming increasingly important in human health. Early diagnosis is a prerequisite for successful treatment and requires identification of Acanthamoeba at the genotypic level. The genus Acanthamoeba consists of both pathogenic and non-pathogenic species and has been recently classified into 13 different genotypes, T1-T12 and T14. More importantly, 95% of Acanthamoeba isolates that produce keratitis belong to T4 genotypes. In this study, we attempted to determine whether predominance of T4 isolates in Acanthamoeba keratitis is due to greater virulence or greater prevalence. We isolated 18 Acanthamoeba isolates from environmental samples in Ankara, Turkey and determined their pathogenic potential by means osmotolerance, temperature tolerance and in vitro cytotoxicity assays using corneal epithelial cells. Ribosomal DNA sequencing revealed that 10 isolates belong to T2, 5 belong to T3, 2 belong to T4 and one belongs to T7 genotype. As expected, T3 and T4 isolates exhibited the most pathogenic traits and were osmotolerant, temperature tolerant and exhibited severe corneal epithelial cell cytotoxicity indicating their pathogenic potential. Overall these data indicate that high frequency of T4 isolates in keratitis cases may well be due to their greater virulence. This is the first report presenting environmental distribution of Acanthamoeba in Ankara, Turkey

Competitive formation of spiro and ansa derivatives in the reactions of tetrafluorobutane-1,4-diol with hexachlorocyclotriphosphazene: a comparison with butane-1,4-diol

Reaction of hexachlorocyclotriphosphazene, N3P3Cl6 (1), in two stoichiometries (1:1.2 and 1:3) with the sodium derivative of the fluorinated diol, 2,2,3,3-tetrafluorobutane-1,4-diol, (2), in THF solution at room temperature afforded six products, whose structures have been characterized by X-ray crystallography and 1H, 19F and 31P NMR spectroscopy: the mono-spiro compound, N3P3Cl4(OCH2CF2CF2CH2O), (3), its ansa isomer, (4), a di-spiro derivative N3P3Cl2(OCH2CF2CF2CH2O)2, (5), its spiro-ansa (6) and non-gem cis bis-ansa (7) isomers and a tri-spiro compound N3P3(OCH2CF2CF2CH2O)3, (8). The tri-spiro derivative (8) was also formed in the reaction of the ansa compound (4) with diol (2) in a 1:3 ratio in THF at room temperature. The reactions of (1) with step-wise additions of (2) were also investigated at low temperature (-780C) to give the same range of products as at room temperature. The results of all reactions are compared with previous work on the reactions of (1) with butane-1,4-diol/pyridine mixtures and with the reaction of hexafluorocyclotriphosphazene, N3P3F6 (9), with the silyl derivative of the diol (2), (Me3SiOCH2CF2)2, in a 1:0.4 mole ratio in the same solvent, THF

Stereoisomerism in pentaerythritol-bridged cyclotriphosphazene tri-spiranes: spiro and ansa 1,3-propanediyldioxy disubstituted derivatives

Four isomeric products were isolated and purified from the reaction of 1,3-propanediol with the tetra-spirane cyclophosphazene-organophosphate compound (1): viz. the di-monospiro (2a), di-monoansa (2b) and two monospiro-monoansa derivatives (2c) and (2d). It is shown by 31P NMR spectroscopy on addition of a chiral solvating agent (CSA) that both the di-monospiro (2a) and di-monoansa (2b) derivatives are racemates, as expected, whereas no splitting of NMR signals occurred on addition of CSA to solutions of (2c) and (2d). It is found by X-ray crystallography that the two monospiro-monoansa spirane derivatives, (2c) and (2d), are meso diastereoisomers, which represent a new case of the stereochemistry of bis di-substituted cyclophosphazene derivatives of (1). It is also observed from the 31P NMR spectrum of the reaction mixture, supported by the yields of pure compounds, that formation of a spiro group is about 4.5 times more likely than that of an ansa moiety under the conditions of the reaction

Structural investigations of phosphorus-nitrogen compounds. 7. Relationships between physical properties, electron densities, reaction mechanisms and hydrogen-bonding motifs of N3P3Cl(6-n)(NHBut)(n) derivatives

A series of compounds of the N3P3Cl(6-n)(NHBut)n family (where n = 0, 1, 2, 4 and 6) are presented and their molecular parameters are related to trends in physical properties, which provides insight into a potential reaction mechanism for nucleophilic substitution. The crystal structures of N3P3Cl5(NHBut) and N3P3Cl2(NHBut)4 have been determined at 120K and those of N3P3Cl6 and N3P3Cl4(NHBut)2 have been re-determined at 120K. These are compared with the known structure of N3P3(NHBut)6 studied at 150K. Trends in molecular parameters (phosphazene ring, P-Cl & P-N(HBut) distances, PCl2 angles and endo- and exo-cyclic phosphazene ring parameters) across the series are observed. Hydrogen-bonding motifs are identified, characterised and compared. Both the molecular and hydrogen bonding parameters are related to the electron distribution in bonds and the derived basicities of the cyclophosphazene series of compounds. These findings provide evidence for a proposed mechanism for nucleophilic substitution at a phosphorus site bearing a PCl(NHBut) moiety

An alternative anterior tension free preperitoneal patch technique by help of the endoscope for femoral hernia repair

AbstractBackgroundFemoral hernias are relatively uncommon and have a higher risk for strangulation and incarceration. We introduce an alternative anterior tension free inlay patch technique by help of the endoscope for femoral hernia repair.MethodCharacteristics of patients undergoing femoral hernia repair between March 2006–April 2011 and description of the surgical technique is presented.ResultsWe analyzed our experience with this technique in 26 consecutive patients with femoral hernias (1 bilateral, 15 right, 10 left femoral hernia) in 5 year period. Seven of these 26 femoral hernias were recurrent and 2 of them were concomitant with inguinal hernia. Mean operation time was 30.0 ± 12.1 min. Seroma was seen in 2 patients at postoperative 1st week. There were no; hematoma, wound infection and separation of wound edges and early recurrence at postoperative 1st week and 1st month. The mean follow up period was 41.8 ± 18.2 months. All of 22 patients who were contacted were satisfied with the operation. There was no recurrence, chronic pain and foreign body feeling in any patient at the end of the follow-up period.ConclusionThis feasible and safe alternative anterior inlay patch repair might be used in all femoral hernias with the exception of the ones requiring intestinal resection

Efficient non-degenerate two-photon excitation for fluorescence microscopy

Non-degenerate two-photon excitation (ND-TPE) has been explored in two-photon excitation microscopy. However, a systematic study of the efficiency of ND-TPE to guide the selection of fluorophore excitation wavelengths is missing. We measured the relative non-degenerate two-photon absorption cross-section (ND-TPACS) of several commonly used fluorophores (two fluorescent proteins and three small-molecule dyes) and generated 2-dimensional ND-TPACS spectra. We observed that the shape of a ND-TPACS spectrum follows that of the corresponding degenerate two-photon absorption cross-section (D-TPACS) spectrum, but is higher in magnitude. We found that the observed enhancements are higher than theoretical predictions.Published versio

Conformational studies of bipyrimidine-based mesogens by combination of DFT calculations and temperature-dependent infrared studies

International audienceCombination of DFT calculations and solid-state temperature-dependent infrared spectroscopy has confirmed that the central core of recently developed bipyrimidine-based mesogens is not flat, i.e. do not adopt a disc shape, inside the columnar liquid-crystalline phase. For this purpose, the intensities and the frequency shifts of the most sensitive C–N and C–C bands of the central bipyrimidine core have been studied as a function of the temperature and of the dihedral angle. The results support the reported packing model in which the molecules are interdigitated alternatively along their long axis and their short axis to form columns inside the mesophase

Novel Surgical Treatment of an Intraretinal Juxtapapillary Hemangioblastoma Using Intraocular Diathermy Forceps:A Case Report

The surgical treatment of intraretinal juxtapapillary retinal hemangioblastomas (JRHs) was previously contraindicated because of the significant risk of collateral damage to the macula and optic nerve. This case report discusses the effectiveness and safety of a novel surgical technique using intraocular bipolar diathermy forceps to coagulate feeder and draining blood vessels of an intraretinal JRH. The patient suffered from bilateral retinal hemangioblastomas with loss of visual function in one eye and the development of an intraretinal JRH in the other eye. Despite intensive treatment with intravitreal bevacizumab and subconjunctival triamcinolone acetonide, growth of the intraretinal JRH continued, macular exudation worsened, and visual acuity decreased. Surgical treatment was undertaken in which, first, the feeder and draining vessels of the JRH were identified by comparing the retinal imaging of the JRH with the imaging before the emergence of the JRH 4 years earlier. Then, retinal incisions were made above the blood vessels and parallel to the nerve fibers during a pars plana vitrectomy. Lastly, these vessels were lifted above the retinal surface and coagulated using intraocular diathermy forceps. Postoperatively, macular edema reduced, and visual acuity increased and remained stable for about 6 months. Using intraocular diathermy forceps, this case report demonstrates effective and safe intraretinal JRH blood vessel coagulation above the retinal surface. This novel surgical approach was able to delay the deterioration of visual acuity due to tumor growth and exudation in this patient. This suggests that coagulation with intraocular diathermy forceps can be considered an additional surgical treatment option for JRHs, especially those with an intraretinal growth pattern.</p